The UV filter blocks UV light that may discolor film when photographing outdoors. The UV filter is also a great way to keep dust and scratches off of your lens. Protecting your lens with a filter is a lot less expensive than replacing a damaged lens.These filters offer both amateur and professional photographers HOYA"s famous quality at reasonable prices. They have coatings applied to both surfaces to suppress reflection and increase light transmission. There are a few exceptions in the special effects range which, due to the special materials used in construction, do not have coatings applied.